Add `prometheus_simple` receiver to the k8s distribution

[ChristianCiach]

The k8s distribution contains the prometheus receiver, but is missing the prometheus_simple receiver, which is (as far as I understand) a simpler interface for common use cases.

In fact, the receiver_creator documentation shows how to combine the receiver_creator receiver, the k8s_observer extension and the prometheus_simple receiver here: https://github.com/open-telemetry/opentelemetry-collector-contrib/tree/main/receiver/receivercreator#examples

So I was very surprised when this example was immediately rejected:

unable to lookup factory for receiver "prometheus_simple"

Pinging @fatsheep9146 as code-owner for this receiver. Maybe the owners have good reasons to not include this receiver in the k8s distribution?

[ChristianCiach]

Is this the right project for this issue?

I believe this receiver does not violate any of the inclusion rules of the k8s distribution. The prometheus receiver is already included, and so is the receivercreator receiver. But the latter cannot be used (at least in "discovery" mode) together with prometheus receiver, as the discovery feature only supports receivers that allow the configuration of an endpoint attribute. That's where the simple_prometheus receiver comes in.

[mowies]

I think it reasonable to introduce the simple prom receiver to the k8s distro. Let's see what others think here maybe.
WDYT @open-telemetry/collector-contrib-maintainers ?

[atoulme]

That works for me.

[mowies]

@ChristianCiach is this still relevant?

[ChristianCiach]

@ChristianCiach is this still relevant?

Yes :)

[mowies]

then i think you could go ahead and create a PR adding the receiver to the k8s distro 👍🏼

[ChristianCiach]

@mowies I won't have access to a regular PC for the next four weeks or so, so a PR will have to wait until then.